What is CNC Precision Machining? All You Need to Know

CNC precision machining

CNC precision machining is one of the most used part manufacturing methods today. It offers many benefits, which include reduced costs and rapid production. If you’re considering this parts manufacturing method, we suggest you read this post first. It discusses the CNC process, techniques, and benefits.

What is CNC Precision Machining?

CNC precision machining is a computer-controlled process where motorized tools remove material to shape a workpiece. The raw material can be metal, plastic, and sometimes wood or rubber.

Most often, the process involves metals. CNC machining happens automatically with the help of a computer program. The program uses the part’s design file to move the workpiece or tools, ensuring excellent precision and accuracy.

The most basic numerical control machine is a 2-axis type with only an x and y-axis. The number of axes can be as high as 12 to achieve higher precision levels. Next, we compare computerized machining equipment with the traditional manual types.

Conventional vs. CNC machining equipment
Conventional vs. CNC machining equipment
Resource: https://youtu.be/ukUbDfPuvM0?si=ZqbxbNhSmQIkdjZa

Difference Between CNC and Conventional Machine.

CNC means computer numerical control. It denotes the use of computer instructions to run the machining equipment. That means the process requires minimal human interference.

On the other hand, the traditional method requires the operator to manually move parts. Numerical control differs from the manual or conventional method in the following ways:

  • CNC automates the entire process, making it faster and more efficient than the traditional method
  • High precision CNC machining offers a higher degree of repeatability than the conventional method and process
  • CNC machined parts are of higher quality with the possibility of more complex design than when using the traditional manual method
  • The computerized method reduces human errors. The traditional process, being largely manual, is prone to mistakes
  • Another difference between CNC and conventional machine technology is the skills needed. The manual method requires more skill than the computerized process.
Precision machining process
Precision machining process
Resource: https://www.youtube.com/watch?v=3Ky6Nhov4ts

CNC Precision Machining Process

The precision machining process begins with designing the part using computer software. Depending on the part’s application requirements, the manufacturer then determines the required material. The next step involves writing a control code before working on the part.

Model Creation

A designer uses CAD software to create a 2D or 3D model of the required part. The model represents the finished part, both in look and dimensions. Once the model is approved, the process can move on to the next stage, where the material to use is selected.

Material Selection

The desired material is selected. Typical options include metals and plastics. The material must be easy to machine. The different metal and plastic types that you can machine are given below.

  • Metals – aluminum, brass, copper, bronze, steel, stainless steel, and titanium
  • Plastics – various plastic types including ABS, PC, POM, PA, PMMA

Programming

The CAM program generates code from the design file to run the machining equipment. This is a custom code and usually either a G-code or M-code. After programming, the process of cutting the workpieces can now commence.

Processing

The machining process can now begin. It involves removing material from a workpiece or subtractive manufacturing. Various methods or techniques are used. They range from milling and grinding to drilling and laser cutting.

Finishing


The precision machined part may require additional processing where it receives a coat to improve its look. It may be electroplated, for example, or applied with a powder coating. Other finishing methods include bead blasting and painting.

CNC machined gears
CNC machined gears
Resource: https://www.researchgate.net

What are the Advantages of CNC Precision Machining?

Computer-controlled machining benefits range from increased accuracy to higher production speeds. It’s also a cost-effective process that allows the creation of complex designs. These CNC machining advantages are explained below.

High Accuracy Levels

Precision CNC, being a computer-controlled process, is highly accurate and has minimal error possibilities. The accuracy level ranges from 0.0002″ to 0.0005.”That makes it suitable for high-precision parts, such as those used in automotive and aerospace applications or those requiring higher tolerances.

Increased Speed

Manufacturers produce parts faster, given the higher speeds of automated processes and the higher level of repeatability. This attribute can lower costs for projects with higher production runs. It also allows clients to meet product-to-market deadlines when receiving machining services.

Complex Parts

Precision machines allow the production of intricate parts. That’s because the workpiece and cutting tools are moved by a computer program. The computerized motion produces complex designs quickly, unlike when the equipment is manually controlled.

Reduced Cost

It requires minimal labor, given that most steps do not require human intervention. In addition, it eliminates the need for expensive tooling, significantly reducing upfront costs. This benefit also makes it a cost-effective option for low-volume production.

CNC milling
CNC milling
Resource: https://www.youtube.com/watch?v=hQPvRM2gaZU

Types of Precision Machining Technologies

CNC precision machining is a general term that means using computerized numerical control to cut and shape parts using a written program. Various techniques are used. Here’s a collection of the most popular technologies:

CNC Turning

In CNC turning, a tool removes material from a round stock piece, although square and other shapes may be used. It typically produces cylindrical finished parts. In this method, the workpiece rotates while the tool remains stationary.

CNC Milling

Milling means using rotary multi-point cutting tools to carve out a block substrate or blank. The workpiece is typically mounted on a movable table. The mill may use 3-axes or more in advanced milling.

CNC Drilling

Rotating drill bits cut cylindrical holes into the stock piece. Various bit sizes and shapes are used depending on the required hole type and diameter. The drill shape also ensures the machined material or chips do not fall into or near the hole.

CNC Grinding

This machining method uses a rotary wheel to cut stock pieces. Grinding is mainly used to produce cylindrical components. It’s also commonly used to finish parts. Grinding offers high precision levels but is a relatively slower process.

Laser Cutting

High-power lasers are focused on the material, and the resulting heat vaporizes the material from the workpiece. Laser cutting is typically used to produce high-precision parts for demanding applications. It involves using different laser types, but mainly CO2 and solid-state lasers.

Electric Discharge Machining

Also called EDM, this method involves using an electric arc or discharge to remove material from the stock piece. It offers the advantage of less noise, like laser cutting. However, it has material limitations since it can only work if the material is conductive.

Precision machining engine block using CNC equipment
Precision machining engine block using CNC equipment
Resource: https://www.enginebuildermag.com

Precision CNC Machining Applications

CNC machining helps produce parts for application in many industries today. Among the many applications that you can use the process for include the following:

Parts Manufacture

Precision machining is widely used to produce automotive, construction, medical, and aerospace components. In all these applications, the process allows the creation of complex components with high accuracy levels.

Industrial Tooling

Machining is a quick and cost-effective way of producing industrial tooling components such as molds. It only requires designing 2D or 3D models and a programmer to write the process code or the program telling the machine where to cut.

Prototyping

Before a part is mass-produced, precision machining is first used to create its prototype. That’s because it’s a quicker method that requires no tooling, reduces costs, and allows for rapid prototyping.

Making Carvings

Decorative pieces are produced using CNC-controlled machinery to obtain stunningly complex designs. In addition to precision and accuracy, using this method to make decorative or ornamental pieces offers the advantage of reduced costs.

Conclusion

CNC precision machining is one of the most versatile parts manufacturing methods. In addition to making functional components, you can use it for prototyping and tool making or to carve out decorations. It produces high-quality parts and doesn’t require expensive tooling, which makes it a cost-effective solution for a parts project.

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